The present invention relates to the selection of a destination for route calculation in a vehicle navigation system. More specifically, the present invention provides a means by which a user of a vehicle navigation system may conveniently select a city as a destination even where the streets of that city have not been digitized and included in the system's map database.
In currently available vehicle navigation systems, the user may specify a desired destination in a variety of ways. For example, when it is known, the user may specify the street address of the destination. Alternatively, the user may specify an intersection of two roads in the vicinity of the destination. Once the user selects one of these alternative methods for designating the destination, the user is typically prompted to select a city from a displayed city list. In response to selection of a city, the user is then prompted to select the appropriate street or streets from a displayed list of streets corresponding to the selected city. Obviously, for either of these alternatives to be available, the streets of the city in which the destination is located must be represented by digitized data in the system's map database. However, because there are many small towns outside of major urban areas which have not yet been digitized, the map databases commonly used in commercially available systems do not have much, if any, street data for such towns.
FIG. 1 is a flowchart 100 illustrating a particular method for selecting a destination for route calculation using a street address. Once the user selects the street address option for specifying a destination (102), a city list 152 is presented (104) which includes all of the cities for which digitized street data exist in map database 154, i.e., digitized cities. Upon selection of a particular city by the user (106), a street name list 156 is presented (108) which includes all of the streets in map database 154 corresponding to the selected city. Upon selection of a street name by the user (110), the user is prompted to enter a street address (112). Once a valid street address is entered (114), the navigation system employs the specified address as the destination for route calculation (116).
FIG. 2 is a flowchart 200 illustrating another method for selecting a destination for route calculation using an intersection. Once the user selects the intersection option for specifying a destination (202), a city list 152 is presented (204) which includes all of the cities for which digitized street data exist in map database 154, i.e., digitized cities. Upon selection of a particular city by the user (206), a first street name list 156 is presented (208) which includes all of the streets in map database 154 corresponding to the selected city. Upon selection of a first street name by the user (210), a cross street name list 252 is presented (212) which includes all cross streets corresponding to the selected street name. When a cross street is selected (214), the corresponding intersection is then used as the destination for route calculation (216).
As discussed above, when a user indicates a desire to designate a specific street address or intersection, the user is typically presented with a list of cities. However, if the streets of the town in which the destination is located are not included in the system's map database, the town is not included in the city list. That is, the city list displays only cities and towns for which digitized street data are stored in the map database. Non-digitized cities are not represented in the city list.
As an alternative to the destination selection methods described above, some systems also allow the user to specify a point of interest (POI) such as, for example, an amusement park or a restaurant. In some systems, city centers or downtown areas are included as a POI category. In response to the selection of the city center category, a list of cities and towns is displayed. In contrast with the city list described above, this city center list includes towns for which digitized street data are not available. The centers or downtown areas of such towns are represented in the map database as a single location with reference to, for example, a highway which passes through the town and for which map data are available.
FIG. 3 is a flowchart 300 illustrating a method for selecting a destination for route calculation using points of interest (POI) such as, for example, amusement parks, museums, restaurants, and downtown areas or city centers. When a user of the vehicle navigation system selects the POI option (302), a list of POI categories 352 is displayed (304) which includes a number of categories of points of interest stored in map database 154. When the user selects a POI category (306) and the category is city centers (308), a city center list 354 is displayed (310) which includes all of the cities in map database 154 regardless of whether database 154 has digitized street data for the listed cities. That is, both digitized and non-digitized cities are represented in city center list 354. Once the user selects one of the city centers (312), the city center is used as the destination for route calculation (318). Where, on the other hand, some other POI category is selected, the appropriate POI list 356 corresponding to the selected category is displayed (314). Individual POI lists 354 and 356 may either be generated during database compilation, or on the fly during system operation from a single large POI list which includes POIs across all categories. Upon selection of a particular POI (316), the selected POI is used as the destination for route calculation (318).
The problem with currently available systems is that once a user selects the street address or intersection options, it is not apparent to the user why a particular city or town is not included in the displayed city list. Neither is it apparent that a city omitted from the city list might be included in the more inclusive city center list among the POI categories. This tends to be confusing for many users who justifiably assume that the system cannot be used to navigate to the desired destination. This, in turn, defeats the purpose of providing a vehicle navigation system. It is therefore desirable to provide a method for selecting a destination in a vehicle navigation system which allows the user to more easily identify and designate towns for which street data are not available.